Heat recoverable articles have found widespread acceptance in employment as seals or other closures in the repair and protection of generally tubular conduits or as marking sleeves for wire identification. Typically, such articles have comprised heat shrinkable tubular sleeves which describe in cross section an integral, closed curve. Among the heat recoverable sleeves so configured are those produced according to Cook U.S. Pat. No. 3,086,242 and Evans U.S. Pat. Nos. 3,894,731; 3,985,852 and 4,032,010, the disclosures of which are incorporated herein by reference.
Materials, both organic and metallic, capable of being rendered heat recoverable are well known. An article made of such materials can be deformed from an original, heat-stable configuration to a second, heat-unstable configuration. The article is said to be heat recoverable for the reason that, upon the application of heat alone, it can be caused to revert, or to attempt to revert, from its heat-unstable configuration to its original, heat-stable configuration.
While tubular sleeves are generally satisfactory in many applications, they require the provision of a free end in the cable or wire to be identified over which the sleeve can be slipped. That manner of application is often manifestly inconvenient, notably in repair cases or otherwise where the identification has to be changed after the cable or wire has been already terminated.
There have been proposed various heat-recoverable wrap-around closures which for their application do not require a free end of the substrate to be installed, but they do require some mechanical joinder of the edges and thus would not be convenient for use as sleeve markers. There also have been proposed various tags that can be fastened onto wires by means of tie-wraps but, again, these are not very convenient to use in practice.
Actioncraft Products manufactures a split-sleeve laminated product which features an easy "snap-on" installation on wires already terminated. However, due to the method of manufacture of these markers, they are delivered pre-printed, which entails considerable delays every time cable or wire rerouting occurs since new markers need to be printed at some remote site. Of course, the same delays would be encountered should new markers of this type be required for any other purpose.
Wrap-around sleeves have also been proposed in Evans U.S. Pat. Nos. 3,847,721 and 3,988,399 and Sovish et al. U.S. Pat. No. No. 3,899,807, the disclosures of which are incorporated herein by reference. Evans discloses articles rendered involutely heat recoverable by differentially annealing a molecularly oriented unitary polymeric layer so as to provide an anisotropic gradient through the thickness thereof. Sovish et al. discloses articles rendered involutely heat recoverable by lamination of a first heat recoverable layer to a second, relatively non-heat recoverable layer which resists linear recovery of the first such that the laminated article curls upon recovery. It is believed that the Evans and Sovish et al. articles have not met with commercial success primarily due to the circumstance that it is difficult to control the final shape of the article.
Various others have proposed the profile extruding of materials for a variety of purposes. Among these are Brandeis U.S. Pat. No. No. 208,363, Allen U.S. Pat. No. 2,613,620, Ruck et al. U.S. Pat. No. 2,952,037, Nevin et al U.S. Pat. No. 3,461,499, Opfell U.S. Pat. No. 3,558,420 and Behr U.S. Pat. No. 3,848,035. However, none of these relate to wrap-around heat-recoverable sleeves.
It can thus be appreciated that the need for a heat recoverable wrap-around article which does not require for its application to a substrate the presentation of a free end thereof remains unfulfilled.
Accordingly, it is an object of the invention to provide an improved heat recoverable wrap-around article which does not require for its application to a substrate the presentation of a free end thereof.
It is a further object of the invention to provide an improved heat recoverable wrap-around article which is amenable to marking printed matter thereon at the time of use.
It is still another object of the invention to provide an improved heat recoverable wrap-around article which is convenient and easy to use.
These and other objects of the invention will become more apparent after reference to the following description considered in conjunction with the accompanying drawings.